Flux Crystal Growth, Crystal Structure, and Magnetic Properties of a Ternary Chromium Disulfide Ba(9)Cr(4)S(19) with Unusual Cr(4)S(15) Tetramer Units

[Image: see text] A new ternary chromium disulfide, Ba(9)Cr(4)S(19), has been grown out of BaCl(2) molten salt. Single-crystal structure analysis revealed that it crystallizes in the centrosymmetric space group C2/c with lattice parameters: a = 12.795(3) Å, b = 11.3269(2) Å, c = 23.2057(6) Å, β = 104.041(3)°, and Z = 4. Ba(9)Cr(4)S(19) comprises four face-sharing Cr-centered octahedra with disulfide ions occupying sites on each terminal face. The resulting Cr(4)S(15) tetramer units are isolated by nonmagnetic Ba-centered polyhedra in the ab plane and barium disulfide (=Ba(4)(S(2))(2)) layers along the c-axis. Following the structure analysis, the title compound should be expressed as [Ba(2+)](9)[Cr(3+)](4)[(S(2))(2–)](4)[S(2–)](11), which is also consistent with Cr2p X-ray photoemission spectra showing trivalent states of the Cr atoms. The unique Cr-based zero-dimensional structure with the formation of these disulfide ions can be achieved for the first time in ternary chromium sulfides, which adopt 1–3 dimensional frameworks of Cr-centered polyhedra.